Drying apparatus having operation sequence control



Apnl 25, 1950 H. F. GORSUCH 2,505,041

DRYING APPARATUS HAVING OPERATION SEQUENCE CONTROL Filed Dec. 29, 1945 2Sheets-Sheet 1 INVENTOR HAROLD F. GORSUCH.

WIT QESSEYS: 8 Fla. 3. 7 BY ATTORNEY April 25, 1950 H. F-. GORSUCH2,505,041

DRYING APPARATUS mvmc OPERATION szqmaucs coN'noL Filed Dec. 29, 1945 2Sheets-Sheet 2 I INVENTOR- HAROLD F. GORSUCH.

&. I I @QQW ATTORNEY WITNESSES:

Patented Apr. 25, 1950 DRYING APPARATUS HAVING OPERATION SEQUENCECONTROL Harold F. Gorsuch, Mansfield, Ohio, assignor to WestinghouseElectric Corporation, East Pittsburgh, Pa., a corporation ofPennsylvania Application December 29, 1945, Serial No. 638,353

7 Claims. 1

My invention relates to drying apparatus, more particularly to apparatusfor drying fabrics or the like, and has for an object to provideimproved apparatus of this kind.

A further object of the invention is to utilize the heat remaining inthe drying chamber of a -quence of drying steps automatically, at theconclusion of which the drier is rendered inactive.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawings, forming a part of this application, in which:

Fig. 1 is a vertical section taken along the line I-I of Fig. 2 andshowing a form of clothesdrier controlled in accordance with myinvention;

Fig. 2 is a sectional view taken along the line 11-11 Of Fig. 1;

Fig. 3 is a diagram of the electrical connections of the controlapparatus used to control the drier shown in Figs. 1 and 2;

Fig. 4 is a view similar to Fig. 1 and showing a second embodiment ofthe invention; and

Fig. 5 is a diagram of the electrical connections for the drier shown inFig. 4.

Reference will now be had to Figs. 1 to 3, inclusive, wherein I haveelected to show my invention applied to a clothes drier of the domestictype and provided with a housing structure ID, the front wall H of whichis provided with an access opening I2 and a suitable hinged door l3 for.closing the opening. The housing II] also includes a back wall It forsuitably supporting a bearing l5 in which a shaft 16 is ournaled. Thelatter supports a basket H for containing the clothes to be dried, whichbasket l'l includes a perforate side wall 18, a number of theperforations being shown at l9. The basket I1 is provided with aplurality of inwardly-extending vanes 2| which function to tumble theclothes during rotation of the basket. The front end of the basket I1 isprovided with an access opening 22 which registers with the accessopening I2 of the housing.

Agenerally cylindrical baille 23 is disposed 2 within the housing l0 andencloses a drying chamber 24 within which the basket rotates. An upperportion of the baille 23 is recessed to provide a cove 25 for housing anelectric heating element, of any well-understood construction andindicated at 26. An air inlet opening 21 is formed in the baille 23 anda relatively large throat 28 is provided at the bottom of the baffle forthe discharge of the heated, humid air from the chamber 24. A pluralityof openings 29 may be provided in the recessed portion of the baffle 23for the ingress of air to the cove 25 and the heating chamber 24.Admission of air from the ambient atmosphere to the housing I0 isafforded by a plurality of louvred openings 3! arranged in one of thewalls of the housing It, such as, for example, the front wall H.

The basket I! and its shaft iii are rotated at a speed of, for example,50 R. P. M. by means of a sheave 32 fixed to the shaft i6 and belted, asshown at 33, to a pulley 34 driven by an electric motor 35. The motor 35also drives a blower 36 having a discharge port 31 extending through thehousing w for the delivery of humid air to the ambient atmosphere. Theinlet eye of the blower 36 is shown at 38 and communicates with achamber 39 formed in the bottom of' the housing Ill and communicatingwith the throat 28. Preferably a lint trap 4| formed, for example, of afiat sheet of screen cloth, is disposed between the throat 28 andchamber 39 for the gathering of lint which may accumulateduring thetumbling of fabrics in the basket. Preferably the lint trap 4| isremovable, by means of a handle 42, through a suitable opening in thefront wall ll of the casing for the periodic cleaning of the lint trap.

As described hereinafter, the operation of the heater 26 and the motor35 is controlled by a timer, generally indicated at 44 and carried by anupper portion of the housing Ill; the timer 44 having amanually-operated knob for initiating operation of the timer andaccessible at the front of the cabinet. The timer 44 will be describedmore in detail hereinafter. Energization of the heater 26 alsocontrolled by a thermostatic switch, generally indicated at 40 andcarried by the baflle 23 in a position where it will reflect thetemperature of the atmosphere within the drying chamber 24.

According to my invention, the timer 44 conditions the heater 26 forenergization accompanied by operation of the motor 35 for apredetermined period of operation of the timer, at the conclusion ofwhich period the heater26 is rendered inactive. The motor 35, however,continues to operate for a second predetermined period of operation ofthe timer to continue the tumbling of the fabrics and the circulation ofair through the chamber 24. It is during the continued operation of themotor 35 that the heat remaining in the chamber 24 subsequent to thedeenergization of the heaters 26 is utilized to complete the dryingoperation, and a concomitant of this operation is that the clothes arecooled to a temperature at which they may be comfortably handled as theyare removed from the basket. 7

Reference will now be had particularly to Fig. 3 for a diagrammaticrepresentation of the timer and the electrical circuits between thevarious electrical translating devices, referred to heretofore. Thetimer 44 includes three switches 46, 41 and 48, all of which are biasedto their open position and actuated to their closed position byrespective cams 49, 50 and 5|. The cams 49 to 5|, inclusive, are fixedto a shaft 52 which is rotated at a relatively slow speed by means of aspeed-reducing mechanism 53 driven by a timing motor 54. The latter maybe of the synchronous type usually employed for driving clocks. Theshaft 52 is provided with a knob 55 which may be manually actuated toadvance the cams 49 to 5|, inclusive, when initiating operation of thetimer. A slip clutch 56 is employed to permit rotation of the shaft 52relative the speed-reducing mechanism 53 during a manual adjustment ofthe cams, and which also functions to drive the shaft 52 duringoperation of the timer motor 54. Regardless of whether the shaft 52 ismanually actuated or driven by the motor 54, rotation is clockwise asshown by the arrow on the knob 55.

The source of power for the apparatus is defined by line conductors L1and L2 and a conductor N. These three conductors are usually connectedto a three-wire, single phase Edison distribution system wherein thepotential across the line conductors L1 and L2 approximates 230 volts,while the potential from either of the line conductors L1 and L2 to theneutral conductor N is approximately 115 volts. As shown, the conductorsL1 and L2 are respectively connected to one side of each of the switches46 and 41, and the conductor L1 is also connected to one side of theswitch 48 by means of a conductor 58. The opposite side of the switch 46is connected, by means of a conductor 59, to one terminal of the heater26 through a pair of contacts 6| forming a part of the structure of thethermostat 46.

The thermostat 46, which may be of any wellunderstood construction,includes a heat-actuated member, such as a bimetal disc 62, which, whenthe temperatureof the atmosphere within the heating chamber 24 is belowa predetermined value, bridges the contacts 6| for energizing the heater26. Conversely, when the temperature of the air within the chamber 24 isabove a predetermined value, the bimetallic element 62 snaps to theposition shown in dotted lines in Fig. 3, for opening the heater circuitat the contacts 6|. In the latter position of the thermostatic element62, a pair of contacts 63 are bridged for energizing the timer motor 54,further reference to which will be made hereinafter. The oppositeterminal 41. From this connection, it will be apparent that the motor 35operates during the period of time that the switch 41 is closed. It willalso be apparent that the main heater 26 is conditioned for energizationunder control of the thermostat during periods when the switch 46 isclosed. From the shape of the cams 49 and 5|], it will be seen that theswitch 41 is closed simultaneously with the closing of the switch 46 andthat the switch 41 remains closed for a period of time after the switch46 is opened.

During the heating steps in the drying program, the timer motor isenergized during peri ods when the thermostat 46 is satisfied, or, inother words, when the temperature in the chamber 24 is above the valueat which the thermostatic disc 62 snaps to its dotted line position.Conversely, when the thermostat 40 is calling for heat, the timer motor54 is deenergized. As shown, one terminal of the timer motor 54 isconnected by a conductor 66 to one contact 63 of the thermostat 46, theopposite contact 63 being connected to the conductor 59. The oppositeterminal of the timer motor 54 is connected by means of a conductor 61to the neutral conductor N. A switch 68 may be interposed in theconductor 61 for manually rendering the timer motor 54 inactive, thepurpose of which will be referred to hereinafter. The conductor 66 isalso electrically connected by means of a conductor 69 to the movablecontact of the cam-operated switch 48. From this connection, it will beapparent that, when the switch 48 is closed towards the conclusion ofthe heating step in the cycle. the timer motor 54 will be continuouslyenergized regardless of the position of the thermostat 40.

In operating the drier described heretofore, the operator deposits thewet fabrics in the basket l1 and closes the door l3, after which thetimer knob 55 and the cams 49 to 5| are moved angularly from the off"position of the timer to the 011" position thereof, which movement issufficient to close the switches 46 and 41. Accordingly, the heater 26is energized since the thermostat disc 62 is relatively cool and is,therefore, in the position shown wherein the contacts 6| are bridged.The circuit for energizing the heater 26 includes the line conductor L1,the switch 46, conductor 59, the bridged contacts 6|, heater 26,conductor 64, switch 41 and line conductor L2. The main motor 35 is alsoenergized for tumbling the fabrics and for the circulation of airtherethrough by means of a circuit extending from the line conductor L2and including the switch 41, conductors 64 and 65, main motor 35 and aneutral conductor N. Since the contacts 63 and the switch 48 are open,the timer motor 54 is inactive.

The heat generated by the heater 26 at this time progressively increasesthe temperature of the drier structure and the fabrics containedtherein. During theearly stages of this heating step, the rise intemperature within the chamber 24 is relatively slow as a substantialportion of the energy dissipated by the heater 26 is converted to latentheat of vaporization and a relatively small percentage of the energydissipated by the heater is converted to sensible heat. As the dryingprogresses, more energy is converted to sensible heat and less to latentheat so that the of the heater 26 is connected by a conductor 64 7otemperature rise is increased. When the temperato the movable contact ofthe switch 41.

One terminal of the main motor 35 is directly connected to the neutralconductor N, while the opposite terminal is connected by means of a tureof the chamber 24 is increased to a predetermined high value of, forexample, 180 F., the thermostat 46 opens the contacts 6| and closes thecontacts 63. Accordingly, the heater 26 is conductor 65 and theconductor 64 to the switch deenergized and operation of the timer isinitiated since the timer motor 54 is now energized by means of acircuit including line conductor L1, closed switch 48, conductor 89, thebridged contacts G3, conductor 56, timer motor 54, conductor 61 and theneutral conductor N.

The cams 49 to ii are now rotated clockwise at a relatively low speed.During this operation of the timer, the temperature within the chamber24 may drop to a predetermined value for example, 160 F., so that thecontacts 6| are again bridged for energizing the heater 26. and thecontacts 63 are opened, whereupon operation of the timer motor ceases.The heater 26 will be energized and deenergized under control of thethermostat 40 until the timer cams have been advanced suificiently toopen the switch 46 whereupon the heater 26 is deenergized for theremainder of the cycle. At this time, the clothes are substantially dry.I Shortly before the opening of the switch 46, the switch 48 is closedto establish a shunt circuit around the contacts 63 for the continuousenergization of the timer motor 54. This shunt circuit includes theconductors Ll, 58 and 69. It will be understood that the main motor 35continues operation after the opening of the switch 48 as its circuit ismaintained by the closed switch 41.

During the latter part of the drying cycle or after the heater 26 hasbeen deenergized by the openingof the switch. the continued circulationof air through the chamber 24 completes the drying operation. The storedheat is, utilized for this purpose, and since there is a continuous flowof relatively cool air from the ambient atmosphere, the drier structureis cooled as the fabrics are being dried. After a predetermined periodof continuous operation of the timer 8d, the switch 47 is opened by thecam 50. whereupon the main motor 35 is deenergized. Shortly thereafter,the cam opens the switch 48 for de-energizing the timer motor 5%. Theapparatus is now in the ofi position, as shown, and the dried fabricsmay be removed from the basket.

The steps in the drying cycle recited heretofore obtain whether the loadto be dried is heavy or light. However, the total duration of the dryingcycle willbe longer with a heavy load, inasmuch as longer periods ofenergization of the heater are necessary to vaporize the moisture.Conversely, with a light load the periods of en-- ergization of theheater 26 are shorter and the duration of the entire cycle will berelatively short. The wattage of the heater 2d, the amount of airtranslated through the drying chamber 2d and the speed at which thetimer motor 5% ad vances the cams are correlated so that the ma heavy,and when such conditions prevail, it is 8 degree or dampness in thefabrics at the conclusion of the cycle.

Occasionally extremely heavy drying loads are encountered such as, forexample. when a pinrality of heavy throw rugs are to be dried or whenthe amount of molsturein any load is the timer motor. when the load isdried, the

jority of the loads usually dried in apparatus of this kind will requirebut a single setting of the controlknob 55. If the knob 55 is adjustedto its "on position, as indicated, without any addi tional angularmovement of the knob, the fabrics will be thoroughly dried when removedfrom the drier. The operator may, however, in initiating operation ofthe apparatus, advance the knob 55 beyond its on position in order toshorten the time that the switch $6 is closed during the heating cycle.Accordingly, when the cycle is terminated thefahrics are damp in orderto provide for immediate ironing. The amount of dampness remaining inthe fabrics may be selected by the operator when initiating the cycle byadvancing the control knob more or less. In this connection. indicia maybe provided on the knob 55 to guide the operator in. selecting theoperator moves the timer to the "01? position or may advance the timerto the position wherein air circulation only is eflected and then closethe switch 68. Accordingly, the load will be cooled during the operationof the timer to its oil position. The switch 68 is so constructed thatit is retained in its "011 or o position after having been moved toeither one of these positions.

' The drier which I have indicated in Fig. 4 and constituting a secondembodiment of the invention is constructed generally along the linesdescribed heretofore, and parts which are common to both are indicatedby similar reference numerals. This drier is provided with thermostat,indicated at l l for controlling energization of the heater 2G andconstitutes a safety thermostat which prevents overheating of the air inthe chamber 2E. The second thermostat i2 reflects the temperature of thedischarged air and is preferably located in the chamber 39. As shown inFig. 5, the thermostat I2 is constructed generally along the lines ofthe thermostat so, in that it includes a bimetal element 73 which movesfrom the position shown in the drawing to its dotted line position, inresponse to a predetermined temperature of, for example, 180 F. Thisthermostat i2 is, however, of the high differential type and is adaptedto move from its dotted line position to the position shown in thedrawing, when the temperature of the air has been depressed to atemperature of, for example, F. The thermostat?! may be arranged to openits contacts at a temperature of 185 F. and functions as a safety devicewhich in normal operation remains closed.

As shown in Fig. 5, the thermostatic element 73 bridges contacts M,which'indicates that its temperature is below F. When the temperature orthe air in the discharge duct attains 180 F., the element 13 moves toits dotted line position, wherein it bridges contacts 75. The element 73remains in this dotted line position until the temperature has beendepressed to 130 F.

The timer structure associated with Fig. 4 is indicated generally by thenumeral id and includes a pairof cams W and it? which are rotated withthe shaft 52 by the timer motor 5d through the reduction gearing b3. Asin the first embodiment, the shaft 52 may be moved angularly manually bythe knob 55 from an ad position to an on position.

The cam E1 in the on position closes a pair of switches 8i and 82 andthe cam it closes the switch 83. One terminal of the switch BI isconnected to the line conductor Li and the other contact of the switch85 is connected to a ter- 7 mine! of the heater 26 through thethermostat II. The other switch 82 has one of its contacts connecteddirectly to the line conductor In and its second contact connected tothe opposite terminal of the heater 26 through the contacts 16. Oneterminal of the timing motor 58 and one terminal of the main motor 35are electrically connected by a conductor 84 to the stationary contactof the cam-operated switch 83, the movable contact of which is directlyconnected to the neutral conductor N. The opposite terminal of the timermotor 54 is connected by means of a conductor 85 to the line conductorLi through the contacts of the thermostat I2. The opposite terminal ofthe main motor 85 is connected by means of a conductor 86 to the lineconductor Lo.

In initiating operation of the drier shown in Figs. 4 and 5, the timeris advanced to its on" position after the damp clothes have beendeposited in the basket l'l. Accordingly, the switches 8|, 82 and 83 areclosed. Closure of the switches 8| and 82 energizes the heater 26, itbeing understood at this time that the therm stat 12 is relatively coolor at room temperature. The closure of the switch 83 energizes the mainmotor which operates, as described heretofore, to tumble the fabrics inthe basket and to circulate air through the drying chamber 24. Operationof the heater 28 increases the temperature within the chamber 24, theincrease being relatively slow at the beginning of the heating cyclebecause 01 the large amount of water to be evaporated. As the dryingprogresses, the temperature increases rapidly as described heretofore.During this drying operation, the. timer motor 54 is inactive. When thetemperature of the air in the discharge duct attains 180 F., indicatingthe fabrics are substantially dry, the thermostatic element I3 moves toits dotted line position for deenergizing the heater 26 and forenergizing the timer motor 54. The latter thendrives the cams l1 and 18.

When drying a heavy load, the heater 26 will be energized for arelatively long period of time, during which a relatively large amountof heat is stored in the fabrics and the drier structure. Accordingly,the thermostat I2 being of the wide difierential type, a relatively longperiod of time elapses between the opening of the thermostat contacts 24and the reclosing thereof. With a light load, the heating of the fabricsis more rapid and less heat is stored in the drier structure that whenthe load is heavy. Accordingly, the cooling of the thermostat is morerapid and it recloses its contacts I4 in a shorter period of time thanwhen the load is heavy.

During operation with a heavy load, the timer operates to open theswitches 8|, 82 and 83 prior to the reclosing of the contacts 14 by thethermostatic element 13 because, as pointed out heretofore, the largeamount of heat stored in the drier structure prevents early reclosing ofthe thermostatic switch 12. Accordingly, the heater 26 may be energizedonly once during the drying cycle.

From the foregoing description, it will be apparent that I have providedimproved drying apparatus wherein the material being treated is driedand then cooled for handling, a substantial portion of the heatremaining in the material and the drier structure subsequent toterminating operation of the heater being utilized to complete thedrying operation. The various steps in the drying cycle areautomatically efiected by a master control or timer which may beadjusted to vary the degree of drying, the desired degree being obtainedregardless of the weight of the load being dried. This operation isobtained automatically by varying the duration of the period of timethat the heating means is conditioned for-operation in response to theload on the drying apparatus. The cooling step in the cycle is carriedout during a fixed period of time.

What I claim is:

1. In drying apparatus, the combination of means defining a dryingchamber for the material to be dried, means for circulating air throughsaid chamber, means for heating the air, control means for the airheating and air circulating means adjustable from an inactive positionto an active position for initiating operation of the air circulatingmeans and the heating means, a timer for actuating the control means toits inactive position, said control means being effective to terminateoperation of the heating means after a predetermined period of operationof the timer and to terminate operation of the air circulating meansafter a second longer period of operation of the timer, meansresponsi've to a predetermined low temperature of the heated air forenergizing the heating means and responsive to a predetermined hightemperature a of the heated air for deenergizing the heating meansduring periods of operation of the latter, and means responsive topredetermined low and high temperatures of the heated air for,respectively, terminating and initiating operation of the timer.

2. The combination as claimed in claim 1, meluding means renderedeifective after a precontrolling energization of said 'air circulatingmeans and said air heating means, respectiveLv, means for closing saidfirst and second switches when initiating a drying cycle, thermostaticmeans controlling energization of said heating means, said thermostaticmeans eifectirig the energization of the heating means in response to apredetermined low temperature of said air and deenergization of theheating means in response to a predetermined high temperature of saidair, motor-driven timing means for actuating said second switch to itsopen position after a predetermined period of operation of the timingmeans and actuating the first switch to its open position after apredetermined, longer period of operation of the timing means, meansactuated by said thermostatic means for energizing the 9 timing meansduring periods when the heatin means is deenergized and for deenergizingthe timing means during periods when the heating means is energized, andswitch means for energizing the timing means independently of thethermostatic means after a predetermined period of operation of thetiming means, said switch means being eilective to deenergize the timingmeans at the conclusion of the drying cycle.

5. The combination as claimed in claim 4, including a manually-actuatedswitch controlling energization of the timing means and movable, atwill, to an open position for terminating operation of the timing means.

6. In drying apparatus, the combination of means, defining a dryingchamber for the material to be dried, means for circulating air throughsaid chamber, means for heating the air, first and second switchingmeans respectively controlling operation of the air circulating and theair heating means, motor driven timing means actuating the first andsecond switching means for cycling the air heating and air circulatingmeans in a predetermined program, a thermostat movable to first andsecond positions in response, respectively, to predetermined high andlow temperatures of the circulated air, a switch actuated HAROLD F.GORSUCH.

nnrnnnncns crrnn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,675,160 Carroll June 26, 19282,161,847 Blodgett June 13, 1939 2,351,326 Ergbuth June 13, 19442,363,467 Strobridge Nov. 21, 1944 2,398,880 'Broglie Apr. 23, 1946

